Curdlan is used as a polysaccharide thickener in a variety of fields, mainly for applications aimed at improving physical properties, including thickening, gelling, water retention and shape retention.
Although curdlan has an effect even when used as a powder, because it is insoluble in water, achieving satisfactory manifestation of the functions of curdlan in the production of processed foodstuffs and the like has proven difficult.
Curdlan is insoluble in water in acidic through to nearly neutral conditions, and therefore when simple curdlan is added to water, a curdlan precipitate sometimes forms. Because curdlan is soluble in alkaline aqueous solutions, when preparing an aqueous solution of curdlan, a dispersion containing the curdlan dispersed in water and an alkaline solution are prepared separately in advance, and must then be subjected to mechanical mixing or the like using a stirrer or the like.
In this manner, although curdlan does become soluble in water under alkaline conditions, because aggregates (so-called “lumps”) form if the curdlan is simply added directly to an alkali solution, meaning the production of a curdlan solution requires the preparation of two liquids, namely a curdlan aqueous solution and an alkali solution, the production process for a curdlan aqueous solution has tended to be complex (see Patent Document 1). In order to reduce the effort required to prepare this type of curdlan aqueous solution, one possible method involves preparing a mixture in advance containing a powdered blend of curdlan and an alkali agent, and then adding this mixture to water and stirring to obtain a curdlan dispersion, but when a mixture that has been prepared using the pH of the mixed solution as an indicator is added to water, aggregation tends to occur, and producing a uniformly dispersed solution is difficult.
One known curdlan mixture that addresses this problem is a curdlan mixture that uses a coated alkali agent (see Patent Document 2). When this mixture is added to water, because the elution of the alkali is delayed by several tens to several minutes, the curdlan first adapts to the water, and the alkali is then eluted from the coated alkali agent, meaning aggregates are less likely to form. However, preparation of the type of curdlan formulation described in Patent Document 2 requires the preparation of a coated alkali agent.
Accordingly, there is a demand for the development of a curdlan-containing composition which is unlikely to generate aggregates when dispersed in water, and with which a curdlan dispersion can be easily prepared.